1. Field of the Invention
The present invention relates generally to a method of partitioning resources in a Cognitive Radio (CR) wireless communication system and a system supporting the same, and, in particular, to a method of partitioning resources for Base Stations (BSs) and a system supporting the same.
2. Description of the Related Art
The rapid development of wireless communication systems and the emergence of diverse services are a driving force behind the ever-increasing demands for radio resources. However, radio resources, i.e. frequency spectrum, is considered a public asset and thus is subject to strict government regulations. Because most available frequency bands are occupied, there is a great difficulty in frequency band allocation for new wireless communication systems.
As a solution to this problem, CR technology has been proposed. CR senses an already allocated but unused frequency band and shares the frequency band efficiently.
CR is based on point-to-multipoint communications. In a CR wireless communication system, a BS (hereinafter, CR BS) operates radio resources to enable as many Mobile Stations (MSs) as possible to efficiently communicate.
It is reported that wireless communication systems have very low frequency utilization. In this context, CR has been introduced to increase frequency utilization and facilitate deployment of a new wireless communication system. CR was standardized as Institute of Electrical and Electronics Engineers (IEEE) 802.22 Wireless Regional Area Network (WRAN). The IEEE 802.22 WRAN is an application of CR to TV frequency bands, seeking to increase frequency utilization and expand wireless Internet service by sharing unused TV frequency bands for wireless data communications.
CR, which is a technology for managing and partitioning multiple radio channels and detecting interference, is likely to interwork with future-generation wireless communication technologies. For example, CR will likely be effective in providing high-speed data transmission without frequency interference in a shadowing area encountered under a cellular environment or a suburban area requiring an increased cell size.
However, there are many considerations in real application of CR to wireless communication systems. A major consideration is efficient resource allocation. Resource allocation in the CR technology can be considered in the following two ways. One way to address resource allocation is to efficiently use unused radio resources for a CR system among radio resources licensed to legacy wireless communication system. The other way is to partition resources to CR BSs when a plurality of CR BSs are neighboring to each other.
FIG. 1 illustrates a situation requiring resource partitioning to a plurality of CR BSs in a CR system. In the illustrated case of FIG. 1, a new CR BS (a second CR BS) 112 using the same frequency band is added in a radio environment where a first CR BS 111 is servicing. Normal service to an MS is impossible in an overlapped area between service areas of the first CR BS 111 and the second CR BS 112 due to collision between the two CR BSs.
If each of the first and second CR BSs 111 and 112 is aware of the other CR BS based on the CR technology, another channel will be detected and the collision can be avoided. Yet, if all channels are in use, inter-BS interference is unavoidable. Accordingly, there exists a pressing need for partitioning limited radio resources to CR BSs in a radio environment where a plurality of CR BSs are positioned neighboring to each other.